JP2003197485A - Chip solid electrolytic capacitor and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chip solid electronic capacitor and its manufacturing method, which are capable of preventing a cathode terminal from coming off at cutting and of restraining the capacitor from deteriorating its ESR characteristics. <P>SOLUTION: A dielectric oxide film, an electrolytic layer, and a cathode layer are successively laminated on the surface of an anode body for the formation of a capacitor element 2 whose outer surface serves as the cathode layer, wherein the anode body is equipped with an anode lead wire 4 and formed of valve action metal. The capacitor elements 2 are mounted on a lead frame 11, equipped with a plurality of repetitive units each provided with an anode terminal 5 connected to the anode lead wire 4 of the capacitor element 2 and a cathode terminal 6 connected to the cathode layer of the capacitor element 2. The capacitor elements 2 mounted on the lead frame 11, the anode terminals 5, and the cathode terminals 6 are coated with a sheathing resin 3 so as to make the terminals 5 and 6 partially exposed. The repetitive units of the lead frame 11, where the capacitor elements 2 covered with the sheathing resin 3 are located inside are cut into the prescribed shapes for the formation of chip solid electrolytic capacitors. Thin-walled parts 30 and 31 are provided to the lead frame 11 so as to surround the mounting part where the capacitor element 2 is mounted. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a chip type solid electrolytic capacitor which can be used for high density surface mounting mounted on various electronic devices.

[0002]

2. Description of the Related Art A chip-type solid electrolytic capacitor usable for these high-density surface mounting is disclosed in Japanese Patent Laid-Open No. 2001-69.
As proposed in Japanese Patent Publication No. 78, a dielectric oxide film and an electrolyte layer are sequentially laminated on the surface of an anode body made of a valve metal, which has an anode lead wire, and the outer periphery of the anode body serves as the cathode layer. Mounting step of mounting the capacitor element on a lead frame having a plurality of repeating units each having an anode terminal connected to an anode lead wire of the capacitor element and a cathode terminal connected to the cathode layer, and mounting on the lead frame A coating step of coating the capacitor element and the anode terminal and the cathode terminal with an exterior resin so that a part of each electrode terminal is exposed; and the inside of the capacitor element coated with the exterior resin There is known a method for manufacturing a chip type solid electrolytic capacitor including a cutting step of cutting a repeating unit of the lead frame into a predetermined shape.

[0003]

The electrode terminals of the chip type solid electrolytic capacitors obtained by the above-mentioned manufacturing method, especially the cathode terminals, have a small contact area with the exterior resin and the adhesive strength between the exterior resin and the cathode terminals. Becomes weak, and in particular, in the case where a plurality of capacitor elements are mounted vertically and horizontally on the lead frame and is covered with an exterior resin and then cut, it becomes the cathode terminal of the lead frame. At the time of cutting the part, vibration and mechanical stress during cutting are easily concentrated on the chip type solid electrolytic capacitors located on the outer periphery of the plurality of arranged capacitor elements, and the cathode terminal may drop off due to these vibrations and mechanical stress. In some cases, the electrical connection characteristics with the cathode layer of the capacitor element, such as ES Characteristics there was a problem such as a deteriorated.

Therefore, the present invention has been made by paying attention to the above-mentioned problems, and a chip type solid electrolytic capacitor and a cathode type solid electrolytic capacitor which are less likely to drop the cathode terminal by cutting and deteriorate the ESR characteristic and the same. It is intended to provide a manufacturing method.

[0005]

In order to solve the above problems, a chip type solid electrolytic capacitor of the present invention has an anode lead wire and a dielectric oxide film on the surface of an anode body made of valve metal. An electrolytic layer and a cathode layer are sequentially laminated and formed, and a capacitor element whose outer periphery is the cathode layer is connected to an anode terminal connected to an anode lead wire of the capacitor element and a cathode layer of the capacitor element. It is mounted on a lead frame having a plurality of repeating units each including a cathode terminal, and the capacitor element, the anode terminal, and the cathode terminal mounted on the lead frame are covered with an exterior resin so that a part of each pole terminal is exposed. Obtained by cutting the repeating unit of the lead frame in which the capacitor element covered with the exterior resin is formed into a predetermined shape. A chip type solid electrolytic capacitor is characterized by forming the thin portion on the lead frame to surround the mounting portion of the capacitor element of said lead frame. According to this feature, by providing the thin portion on the lead frame so as to surround the mounting portion of the capacitor element, when cutting the outer peripheral portion of the lead frame or the like, vibration or mechanical stress due to these cutting may occur. It is possible to prevent the electrode terminals of the chip-type solid electrolytic capacitor, especially the cathode terminals from being transmitted and applied, so that it is possible to greatly prevent the cathode terminals from dropping due to disconnection and deterioration of the ESR characteristics. It can be reduced.

The chip type solid electrolytic capacitor of the present invention is
It is preferable that the thin portion is a through hole. With this configuration, by forming the thin portion as the through hole, it is possible to prevent further vibration and mechanical stress from being transmitted to and applied to the electrode terminal, particularly the cathode terminal.

According to the method of manufacturing a chip type solid electrolytic capacitor of the present invention, a dielectric oxide film, an electrolyte layer and a cathode layer are sequentially laminated on the surface of an anode body having an anode lead wire and made of a valve metal. A lead having a plurality of repeating units including a capacitor element whose outer periphery is the cathode layer, an anode terminal connected to an anode lead wire of the capacitor element, and a cathode terminal connected to the cathode layer of the capacitor element. A mounting step of mounting on a frame; a coating step of coating the capacitor element, the anode terminal and the cathode terminal mounted on the lead frame with an exterior resin so that a part of each pole terminal is exposed; A chip type including a cutting step of cutting the repeating unit of the lead frame in which the capacitor element covered with the exterior resin is embedded into a predetermined shape. A method of manufacturing a body electrolytic capacitor, the lead frame, is characterized in that it is formed a thin portion so as to surround the mounting portion of the capacitor element. According to this feature, by providing the thin portion on the lead frame so as to surround the mounting portion of the capacitor element, when cutting the outer peripheral portion of the lead frame or the like, vibration or mechanical stress due to these cutting may occur. It can be prevented from being transmitted to and applied to the electrode terminal of the chip type solid electrolytic capacitor, in particular, the cathode terminal, so that the cathode terminal may drop off due to cutting, or the ESR
It is possible to significantly reduce the deterioration of the characteristics.

In the method for manufacturing a chip type solid electrolytic capacitor of the present invention, it is preferable that the thin portion is a through hole.
With this configuration, by forming the thin portion as the through hole, it is possible to prevent further vibration and mechanical stress from being transmitted to and applied to the electrode terminal, particularly the cathode terminal.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (Embodiment) FIG. 1 is a perspective view showing a structure of a chip type solid electrolytic capacitor of the present embodiment, FIG. 2 is a sectional view showing a chip type solid electrolytic capacitor of the present embodiment, and FIG.
It is a figure which shows the shape of the lead frame used for the present Example.

Chip type solid electrolytic capacitor 1 of this embodiment
As shown in FIG. 1, the capacitor element 2 and the anode lead wire 4 led out from one side surface of the capacitor element 2 come into contact with each other by being bent, and are welded to the outer periphery of the anode lead wire 4 by welding. An anode terminal 5 provided with a tongue portion 8 to be connected to the anode terminal 5 is disposed below the capacitor element 2 on the side facing the anode terminal 5 with the capacitor element 2 interposed therebetween.
The capacitor element 2 is connected to the lower surface of the outer peripheral portion of the capacitor element 2 electrically and mechanically with a conductive adhesive 10 and the cathode terminal 6 and a portion except the exposed portions of the anode terminal 5 and the cathode terminal 6. Exterior resin 3 to cover
It is mainly composed of and.

As shown in FIG. 3, the anode terminal 5 used in this embodiment has a tongue portion 8 formed in a ribbon shape so as to project to the side of the region where the capacitor element 2 is mounted. Is formed in such a length that the tongue portion 8 can be brought into contact with the anode lead wire 4 by bending the tongue portion 8 from the lead-out portion of the projecting portion, and the lower surface of the capacitor element 2 and the anode terminal to be mounted. When the upper surface of the capacitor element 5 comes into contact with the upper surface of the capacitor element 2, the anode terminal 5 and the negative electrode terminal 6 are short-circuited via the cathode layer formed on the surface of the capacitor element 2, so that insulation is provided between the lower surface of the capacitor element 2. So that the resin 9 intervenes,
An insulating resin 9 is provided on the upper surface.

The capacitor element 2 is an element conventionally used as a solid electrolytic capacitor element, for example, anodized on the surface of a sintered body obtained by molding and sintering valve metal powder such as tantalum. To form a dielectric oxide film as an anode body, and a capacitor element or the like obtained by laminating a solid electrolyte layer such as manganese dioxide and a cathode layer made of carbon or silver paste on the anode body. It can be used preferably. still,
As the solid electrolyte, those using a polymer electrolyte such as polypyrrole can also be used.

In this embodiment, the anode terminal 5, the tongue portion 8 and the cathode terminal 6 are shaped as shown in FIG.
A plurality of repeating units each consisting of a pair of anode terminals 5 and cathode terminals 6 are arranged to form a lead frame 11 on which a plurality of capacitor elements 2 can be mounted. In the present embodiment, these capacitor elements 2 are formed. 3 × 5 = 15 repeatable units that can be mounted are arranged to form a collective unit that is a sealing region that is simultaneously sealed by the sealing resin 3, and the collective unit seals without providing a gap. While being sealed with the resin 3, the sealing region, which is a set unit of these, is repeatedly arranged in the longitudinal direction of the lead frame 11.

Further, in the lead frame 11 of this embodiment, as shown in FIG. 3, a cutting guide serving as a guide for cutting lines 34 and 35 for facilitating cutting is provided at an outer peripheral position surrounding the set unit. With the holes 32,
At the outer peripheral position of the cutting guide hole 32, through holes 30 and 31 which are the features of the present invention are provided, and when the lead frame 11 is cut, particularly the outer peripheral portion of the set unit shown in FIG. At the time of cutting 11a and 11b, the lead frame 11 and the capacitor element 2 in which vibration and mechanical stress (stress) due to the cutting of these outer peripheral parts are inherent in the assembly unit
It is difficult to be transmitted to.

In this embodiment, the through holes 30 and 31 are provided so as to surround the set unit as described above, but the present invention is not limited to this, and the through holes 30 and 31 are not limited thereto. The portion 31 may be a thin recess.

Further, in the present embodiment, as described above, the through holes 30 and 31 are arranged so as to surround the collective unit, and by doing so, the repeated mounting of the capacitor element 2 is performed. Although the unit is efficiently enclosed, the present invention is not limited to this, and these through holes 30 and 31 may be arranged so as to surround the repeating unit in which the capacitor element 2 is mounted. The arrangement positions of the through holes 30 and 31 may be appropriately selected depending on the arrangement and the like of the repeating unit in the set unit.

The chip type solid electrolytic capacitor 1 of this embodiment will be described below along with its manufacturing process. First, as shown in FIG. 4A, a coating material is applied and dried on the upper surface of the portion of the lead frame 11 to be the anode terminal 5, and the insulating resin 9 is formed. In the present embodiment, as a method of applying these paints, an ink jet nozzle (not shown) is used to apply the paint to the relevant portion of the lead frame 11 so that the thickness of the insulating resin 9 is a thickness that provides sufficient insulation. However, the present invention is not limited to this, and any method can be used as a method of forming these insulating resins 9.

In the application and drying by the ink jet nozzle, the application and the drying are repeated a plurality of times so that a good insulating resin layer without pinholes can be formed.

Further, as the insulating resin 9, a UV-curable resin is used in this embodiment because a coating film having a relatively large thickness can be easily obtained from the height of the solid content of the resin as well as the efficiency of the drying process. Although used, the invention is not so limited.

After the insulating resin 9 is formed, as shown in FIG.
As shown in FIG. 4, the conductive adhesive 10 is applied and formed on the upper surface of the portion to be the cathode terminal 6, and after the application, the capacitor element 2 is mounted as shown in FIG. 4C.

In these conductive adhesives 10, since the cathode layer made of carbon or silver paste is exposed on the lower surface of the capacitor element 2 to be connected, as described above,
From the viewpoint of adhesion to these cathode layers, etc.
The silver-based conductive adhesive 10 used for mounting C or the like is preferably used, but the present invention is not limited to this, and a solder paste or the like is applied instead of the conductive adhesive 10. Then, after mounting the capacitor element 2, the solder paste is melted to fix the capacitor element 2,
It may be mounted.

After mounting these capacitor elements 2, the conductive adhesive 10 is dried or cured to fix the capacitor elements 2, and after the fixing, as shown in FIG. The tongue portion 8 formed by leading out is bent toward the mounting side of the capacitor element 2 and brought into contact with the anode lead wire 4, and the anode lead wire 4 and the tongue portion 8 are formed.
And are connected by welding to electrically connect the anode lead wire 4 to the anode terminal 5.

Next, as shown in FIG. 4E, the lead frame 11 on which the capacitor element 2 is mounted is placed on a ferrite plate 19 which is a flat plate with the non-mounting surface of the capacitor element 2 of the lead frame 11 as the lower surface. And the lower surface and the upper surface of the ferrite plate 19 are brought into contact with each other, and a sealing resin serving as an exterior resin 3 is entirely provided from the mounting side of the lead frame 11 on which the capacitor element 2 is mounted. Is poured into the lead frame 1 so as to have a predetermined thickness so as to be covered with the exterior resin 3.
The exterior atmosphere of No. 1 is made to be a vacuum, so that the exterior resin 3 is filled up to a fine region inside, and then the exterior resin 3 is cured.

As described above, it is preferable to make the external atmosphere vacuum, because the exterior resin 3 can be quickly filled even in a fine region inside, but the present invention is not limited to this.

As the exterior resin 3, an epoxy resin such as epoxy acrylate, which is a molding resin used in the conventional transfer molding, can be preferably used, and at the same time, a heat resistance that can withstand solder heat during mounting on a board. Any resin having properties and capable of obtaining a liquid state at an appropriate heating state or room temperature can be suitably used.

Further, in the present embodiment, as described above, the lead frame 11 on which the capacitor element 2 is mounted is placed on the ferrite plate 19 which is a magnetic material and has high heat resistance to form the exterior resin 3. I am pouring the sealing resin,
This is preferable because the flat ferrite plate 19 can regulate the outflow amount of the sealing resin to the lower surface of the lead frame 11 and reduce the size of the protruding portion 3 ′ of the exterior resin. However, the present embodiment is not limited to this, and these ferrite plates 19
Instead of this, a heat resistant film may be attached to form the exterior resin 3, or the lead frame 11 may be arranged inside the mold to form the exterior resin 3.

It should be noted that it is optional to apply a release agent or the like to the upper surface of these ferrite plates 19 which inhibits adhesion with the exterior resin 3.

After the exterior resin 3 has been appropriately cured, as shown in FIG. 5 (f), the lead frame 11 with the sealing resin is peeled off from the ferrite plate 19, and then the exterior resin 3 is removed. The protruding portion 3 ′ and the lead frame 11 are ground from the lower surface of the lead frame 11 using an elastic polishing body. In this embodiment, as the elastic polishing body, the outer periphery of the side surface of the elastic polishing body is brought into contact with the lower surface of the lead frame 11 for polishing, but the present invention is not limited to this. A disk-shaped body may be used, and the disk surface may be brought into contact with the lower surface of the lead frame 11 and polished.

As described above, not only the protruding portion 3'of the exterior resin but also the entire lower surface of the lead frame 11 is thinly ground so that the lead frame 11 before resin sealing has high strength. It becomes possible to use a thick lead frame which is hard to warp and has excellent handleability, which can improve workability, and the volume ratio of the lead frame 11 in the obtained capacitor can be reduced by making the entire lower surface of the lead frame 11 thin. The volume ratio of the capacitor element 2 occupying in the capacitor can be made higher since it can be reduced as compared with the case where it is not ground and a larger (higher) capacitor element 2 can be mounted. Although preferred, this embodiment is not so limited.

After these grindings, the lead frame 11
As shown in FIG. 5G, the predetermined position of the lead frame 1
By performing R processing so that the corner of 1 becomes a curved part,
The solder accommodating portions 7 and 7'of the anode terminal 5 and the cathode terminal 6 shown in FIG. 2 are formed.

By forming the solder accommodating portions 7 and 7'in this manner, it is possible to sufficiently obtain a contact area with solder when mounting the obtained chip type solid electrolytic capacitor 1 on a substrate. However, it is preferable that the area of the solder fillet exposed on the outer periphery of the chip-type solid electrolytic capacitor 1 can be significantly reduced and the mounting efficiency can be improved. Is not limited to this.

After carrying out the R processing, as shown in FIG.
As shown in (h), after the exposed portion of the lead frame 11 is plated with a metal such as solder plating 14 that can improve the wettability with solder, the chip-type solid electrolytic capacitor 1
On the surface opposite to the exposed surface of the lead frame 11 corresponding to the upper surface of the dicing tape 1 as shown in FIG.
5 is attached, and as shown in FIG.
By forming the cutting groove 16 from the side, the chip type solid electrolytic capacitor 1 having a predetermined shape is obtained.

The present invention has been described above with reference to the drawings. However, the present invention is not limited to these embodiments, and even if there are changes and additions without departing from the scope of the present invention, Needless to say, it is included in the present invention.

For example, in the above embodiment, 1 is set in the set unit.
Although it is designed to incorporate five capacitor elements 2,
The present invention is not limited to this, and it is also possible to incorporate 4, 6, or 9 capacitor elements 2 in these set units, and the number of these elements depends on the shape and size of the set unit. It may be selected appropriately.

In the above embodiment, the tongue portion 8 is used to connect the anode lead wire 4 and the anode terminal 5, but the present invention is not limited to this, and the anode terminal 5 is not limited to this.
Is formed into an L-shape in cross-section so that it can be brought into contact with the lower end of the anode lead wire 4, or a pillow-shaped connecting member is arranged between the anode terminal 5 and the anode lead wire 4 for connection. The connection method between the anode lead wire 4 and the anode terminal 5 may be appropriately selected.

[0036]

The present invention has the following effects. (A) According to the invention of claim 1, by providing the thin portion on the lead frame so as to surround the mounting portion of the capacitor element, when cutting the outer peripheral portion of the lead frame, etc. It is possible to prevent vibration and mechanical stress from being transmitted to and applied to the electrode terminals of the chip-type solid electrolytic capacitor, particularly the cathode terminals.
If the cathode terminal is dropped due to cutting,
It is possible to significantly reduce the deterioration of the R characteristic.

(B) According to the second aspect of the present invention, by forming the thin portion as the through hole, it is possible to prevent further vibration and mechanical stress from being transmitted and applied to the electrode terminal, particularly the cathode terminal. it can.

(C) According to the invention of claim 3, by providing the thin portion on the lead frame so as to surround the mounting portion of the capacitor element, when cutting the outer peripheral portion of the lead frame or the like, It is possible to prevent vibration and mechanical stress due to these cuttings from being transmitted to and applied to the electrode terminals of the chip-type solid electrolytic capacitor, particularly the cathode terminals, so that the cutting may cause the cathode terminals to fall off or the ESR characteristics. Can be significantly reduced.

(D) According to the invention of claim 4, by forming the thin portion as the through hole, it is possible to prevent further vibration and mechanical stress from being transmitted to and applied to the electrode terminal, particularly the cathode terminal. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a chip type solid electrolytic capacitor in an example of the present invention.

FIG. 2 is a cross-sectional view showing a chip type solid electrolytic capacitor in an example of the present invention.

FIG. 3 is a diagram showing a shape of a lead frame used in this embodiment of the present invention.

FIG. 4 is a diagram showing a manufacturing process of the chip-type solid electrolytic capacitor of the present invention.

FIG. 5 is a diagram showing a manufacturing process of the chip type solid electrolytic capacitor of the present invention.

[Explanation of symbols]

1 chip type solid electrolytic capacitor 2 Capacitor element 3 Exterior resin 3'Exterior resin (protruding part) 4 Anode lead wire 5 Anode terminal 6 cathode terminal 7 Solder storage part (anode) 7'Solder housing (cathode) 8 tongue 9 Insulating resin 10 Conductive adhesive 11 lead frame 12 Elastic polishing body 13 recess 14 Solder plating 15 dicing tape 16 cutting groove 19 Ferrite plate (flat plate) 30 through holes 31 through hole 32 Cutting guide hole 34 cutting line 35 cutting line

Claims (4)

[Claims] 1. A capacitor having an anode lead wire and a dielectric oxide film, an electrolyte layer, and a cathode layer, which are sequentially laminated on the surface of an anode body made of a valve metal, the outer periphery of which serves as the cathode layer. The element is mounted on a lead frame having a plurality of repeating units each having an anode terminal connected to the anode lead wire of the capacitor element and a cathode terminal connected to the cathode layer of the capacitor element, and mounted on the lead frame. The capacitor element, the anode terminal, and the cathode terminal are coated with an exterior resin so that a part of each electrode terminal is exposed, and the lead frame in which the capacitor element coated with the exterior resin is contained. Is a chip-type solid electrolytic capacitor obtained by cutting a repeating unit of the above into a predetermined shape, and a mounting portion of the capacitor element of the lead frame. A chip-type solid electrolytic capacitor, characterized in that a thin portion is formed on the lead frame so as to surround the. 2. The chip type solid electrolytic capacitor according to claim 1, wherein the thin portion is a through hole. 3. A capacitor having an anode lead wire and a dielectric oxide film, an electrolyte layer, and a cathode layer which are sequentially laminated on the surface of an anode body made of a valve metal, and the outer periphery of which is the cathode layer. A mounting step of mounting an element on a lead frame having a plurality of repeating units each including an anode terminal connected to an anode lead wire of the capacitor element and a cathode terminal connected to a cathode layer of the capacitor element, and the lead frame. A coating step of coating the capacitor element and the anode terminal and the cathode terminal mounted on a casing with an exterior resin so that a part of each electrode terminal is exposed; and the capacitor element coated with the exterior resin. A method for manufacturing a chip-type solid electrolytic capacitor, comprising: a cutting step of cutting an internal repeating unit of the lead frame into a predetermined shape. A method for manufacturing a chip type solid electrolytic capacitor, wherein a thin portion is formed in the frame so as to surround a mounting portion of the capacitor element. 4. The method for manufacturing a chip type solid electrolytic capacitor according to claim 3, wherein the thin portion is a through hole.